Define Consultants.How does an organization/office/industry choose and appoint a consultant?

'Consultant' is defined as a person who can provide valuable and pertinent advice generally drawn from a high degree of broad administrative, professional, or technical knowledge or experience. A consultant position is one which primarily requires providing advice, views, opinions, alternatives, or recommendations on a temporary and/or intermittent basis.To choosing a Consultants the Office /organization/industry or agency verify the qualifications ,skills and experiences of the candidate and determines the rate of pay commensurate with the level and difficulty of the work to be performed, individual qualifications, internal and external alignment, and availability of qualified candidates.